566
FXUS02 KWBC 220711
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
311 AM EDT SAT OCT 22 2022
VALID 12Z TUE OCT 25 2022 - 12Z SAT OCT 29 2022
...MODEL AND PREDICTABILITY ASSESSMENT AND WEATHER/HAZARD
HIGHLIGHTS...
MODEL AND ENSEMBLE SOLUTIONS HAVE TRENDED TOWARDS BETTER AGREEMENT
RECENTLY AND SHOW FAIRLY GOOD AGREEMENT ON THE OVERALL PATTERN,
BUT INCREASINGLY HAVE RUN TO RUN VARIABILITY AND FORECAST SPREAD
ON THE SMALL-MID SCALE INTERACTIONS/DETAILS THROUGH NEXT WEEK. THE
WPC PRODUCT SUITE WAS PRIMARILY DERIVED FROM A COMPOSITE BLEND OF
THE GFS/ECMWF/UKMET/CANADIAN TUESDAY ALONG WITH THE COMPATIBLE 01
UTC NATIONAL BLEND OF MODELS. SWITCHED TO A BLEND OF STILL
REASONABLY COMPATIBLE GFS/ECMWF AND GEFS/ECMWF ENSEMBLE MEANS
WED-SATURDAY TO SMOOTH OUT COMPONENT DETAIL CONSISTENT WITH
PREDICTABILITY.
A POTENT UPPER TROUGH/CLOSED LOW IS SLATED TO LIFT/SHEAR
NORTHEASTWARD ACROSS THE CENTRAL U.S. AND GREAT
LAKES/MIDWEST/NORTHEAST THOUGH EARLY-MID WEEK. TIMING AND
AMPLITUDE ISSUES REMAIN IN THE GUIDANCE, BUT FORECAST SPREAD HAS
STEADILY DECREASED OVER THE PAST FEW DAYS. THE PATTERN SHOULD
FOCUS GULF MOISTURE AND INSTABILITY INTO THE DEVELOPING LEAD
FRONTAL SYSTEM WHERE STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE
ALONG WITH INCREASINGLY PROGRESSIVE CONVECTIVE RAINS OVER TIME.
THE BEST POTENTIAL FOR MULTIPLE INCHES OF RAINFALL MAY BE OVER THE
MID-SOUTH AND VICINITY TUESDAY COINCIDENT WITH ANY CLOSED
SIGNATURE ALOFT. ADJUSTED NBM QPF THAT SEEMS UNDERDONE WITH
AFTERNOON/EVENING TRAILING COLD FRONTAL CONVECTIVE RAINFALL
POTENTIAL IN DEEPER MOISTURE AND FAVORABLE SUPPORT ALOFT.
PERIODIC UPER TROUGH ENERGY FLOW INTO THE WEST COAST BY EARLY NEXT
WEEK AND AS RENEWED LATER NEXT WEEK CONTINUE TO BE HANDLED
DIFFERENTLY BY THE MODELS DESPITE SOME RECENT IMPROVING AGREEMENT,
MAINLY ON DIGGING/AMPLITUDE. EVEN SO, THE PATTERN DOES SHOW A
DECENT SIGNAL FOR A PERIOD OF MUCH BELOW NORMAL COLD OVER THE
WEST/ROCKIES AND COMPOSITE SYSTEM AMPLITUDES SHOULD STILL FAVOR A
DECENT AND REPEATABLE MODERATE QPF COVERAGE RESPONSE TO INCLUDE
ADDITIONAL HEAVY SNOW THREATS WITH FOCUS OVER FAVORED TERRAIN FROM
THE WEST COAST STATES THROUGH THE GREAT BASIN AND THE ROCKIES. A
MAIN AND POSSIBLY CLOSED SOUTHERN STREAM SYSTEM REMAINS SLATED TO
EMERGE OVER THE SOUTH-CENTRAL TO SOUTHERN U.S. LATE NEXT WEEK INTO
NEXT WEEKEND TO RENEW RAIN/CONVECTION, ALTHOUGH UNCERTAINTY ON
PLACEMENT/AMOUNTS REMAIN HIGHLY VARIABLE.
ELSEWHERE, THE EVOLUTION ASSOCIATED WITH PESKY/LINGERING UPPER
TROUGHING OVER THE MID-ATLANTIC AND TROUGHING FOCUS/INTERCATION
WITH A BLOCKING RIDGE OFFSHORE THE NORTHEAST THROUGH AT LEAST
EARLY NEXT WEEK REMAINS UNCERTAIN AND RUN TO RUN INCONSISTENT IN
GUIDANCE. HOWEVER, THE PATTERN DOES OFFER SUPPORT FOR COASTAL
EFFECTS AND BROAD SCALE MODEST QPF WITH PROTRACTED INFLOW, ALBEIT
WITH DIMINSHING INFLUENCE THROUGH MEDIUM RANGE TIME SCALES.
SCHICHTEL
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES ARE
AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
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